The specific heat of tin and gallium in their stable and undercooled pure liquid states

Abstract

The specific heats, C p , of tin and gallium in their pure liquid state over the temperature range from 632 for tin and 611 for gallium to 425 and 245°K, corresponding to undercoolings of 80 and 58°K respectively have been measured. Over the entire temperature range, the C p for both tin and gallium falls continuously with increasing temperature through their melting point with no singular behavior there. The excess specific heat, ΔC p , of the liquid over the corresponding crystal diverges with falling tempera ture from −0.38 for tin and 0.56 for gallium at their melting point to +0.27 and 1.04 cal/g-atm-°K at the lowest temperature to which the particular specimen could be undercooled. For both tin and gallium, the specific heat at constant volume, C v , of the liquids at their melting point exceeds the Dulong Petit limit value of 3 R, and rises with decreasing temperature. The excess specific heat, ΔC p , as well as ΔC v , of liquid over the corresponding crystal in the undercooled region is attributed to the taking up of configurational entropy with rising temperature.